Enhanced Valve Sealing In Pressurized Dispensing Containers

ABSTRACT

In a valve used for dispensing flowable product from a pressurized container A cup is snapped onto the button at the base of the valve stem so that the upper rim of the cup engages the resilient sealing grommet that surrounds the main portion of the stem. The upper rim of the cup provides a moderately sharp sealing edge so that the pressure against the surface of the resilient grommet is enhanced. This creates a more effective seal than does the relatively broad surface to surface engagement between button and grommet in a standard valve.

BACKGROUND OF THE INVENTION

This invention relates to ensuring that a valve is sealed in apressurized dispensing container when the valve is in its closed state.

The problem of obtaining a fully effective seal in the closed state ofthe valve arises in connection with dispensing products that have gritor particles. Peanut butter is one such product.

It has been found that a number of products cannot be dispensed withthese pressurized containers because there is some minimal leakage or,at least inadequate sealing. The result is that the product deterioratesin some way.

For example, in peanut butter the oil separates out from the rest of theproduct and when dispensed, the oil comes out first, separate from therest of the product. This is entirely unsatisfactory to the end user.

The sealing elements in the valve are the button on the base of thevalve stem and the resilient grommet that surrounds the valve stem. Itis believed that what happens is that particles lodge between the buttonand the grommet providing enough communication across the seal to createsome pressure differential across the product. In peanut butter, thiscauses oil separation when the container is not being used. Regardlessof the exact mechanism, this deterioration of product has been observed.

Accordingly, it is a major object of this invention to provide astructure that assures a complete and effective seal when the valve isin its closed state so that there is no communication across the seal.This will assure that the product is under constant pressure throughoutthe mass of the product while it is on the shelf.

It is a related purpose of this invention to achieve the main object inan inexpensive fashion with a design which does not modify or compromisethe dispensing operation of the container.

It is a further related purpose of this invention to achieve the aboveobjects in a design which involves use of one of the present valvedesigns so as to minimize the cost of adopting the invention.

BRIEF DESCRIPTION

In brief, a device of this invention employs a cup shaped device whichis press fit or snapped onto the valve stem button so that the walls ofthe sealing cup extend above the button. When the valve is sealed, theupper rim of the walls of the sealing cup press into the lower base ofthe grommet providing a seal which is not compromised by the grit orparticles in the product.

To enhance and assure the effective sealing result, the preferred moldedplastic sealing cup has a chamfered wall at its upper rim to provide anarrow sealing edge. The resultant high pressure level assures aneffective seal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view, in partial section, of the valve 10 of thisinvention. FIG. 1 shows the arrangement between the valve stem 12 andgrommet 14 and also shows the sealing cup 16 fitted onto the button 18at the base of the stem 12. FIG. 1 shows the valve 10 in a closed state.

FIG. 2 is a sectional view, on a larger scale, more clearly showing theengagement between the sealing edge 38 which is at the top rim 20 of thesidewall 22 of the sealing cup 16 and the base surface 24 of the grommet14. FIG. 2, shows the closed state of the valve. In that state, thebutton 18 is spaced by a space 42 of a few mils (five mils in oneembodiment) from the base surface 24 of the grommet 14. (Note: one milequals 0.001 inches). This assures that there will be no engagementbetween button 18 and grommet surface 24 that would limit full forceengagement of the sealing edge 38 with the grommet surface 24.

FIG. 3 is a simplified sectional view of the sealing cup 16 showing theannular recess 36 on the inner surface of the sidewall 22 and theannular sealing edge 38 on the rim 20. To simplify presentation, FIG. 3omits the horizontal lines representing the upper edges of the sidewall22.

FIG. 4 is a view in partial section of one presently preferredembodiment having the sealing cup 16A mounted on a thicker than usualbutton 18A. FIG. 4 is adapted for use as a tilt valve.

FIG. 5 is a view in partial section showing an embodiment employing thearrangement of sealing cup 16A and button 18A shown in FIG. 3. FIG. 5shows the use of a resilient tube 44 to provide a restoring forcereturning the valve to its closed state when dispensing pressure isremoved from the nozzle 46. The FIG. 5 design has been designed fordispensing peanut butter.

FIG. 6 is a view in partial section of an embodiment similar to that ofFIG. 5 except that a spring 50 is used instead of the resilient tube 44to provide a restoring force returning the valve to its closed state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 through 3 illustrate a first embodiment. A pressurizeddispensing container (not shown) has a top center opening through whichthe valve 10 extends. The stem 12 of the valve is partially threaded soas to engage the threaded inner surface of a nozzle (not shown). Aresilient grommet 14 extends around the lower portion of the valve stem12 and is held between the button 18 at the base of the valve stem and adownwardly facing ledge 26 on the valve stem 12. In the closed state thegrommet 14 seals the valve stem openings 28. The mounting cup 15 holdsthe valve on the container (not shown).

When the nozzle (not shown) forces the valve stem 12 to move, by eithertilting or by vertical movement, one or more of the valve stem openings28 are exposed to the product held under pressure within the interior ofthe container. The product under pressure will then be forced throughone or more of the openings 28 to a central axial passageway of thevalve stem to exit from an opening at the top of the valve stem into thenozzle (not shown) to be dispensed at the upper end of the nozzle.

The operation of these valves in pressurized dispensing containers iswell known and is described in greater detail in U.S. Pat. No.7,222,758; No. 6,874,663. and No. 5,785,301. In the closed state, theprior art devices do not have the sealing cup 16 and effect a sealingengagement primarily by engagement between the top surface of the button18 and the base surface 24 of the grommet 14. This face to faceengagement is maintained by the pressure of the product within thecontainer on the button 18 and may also be maintained by a restoringforce exerted by engagement of the boot 30 of the grommet 14 against theledge 26 on the stem 12. As shown in FIGS. 5 and 6, a spring 50 orresilient tube 44 may be used to provide the restoring force in lieu ofor in addition to the boot 30.

In particular, where the grommet is soft, the restoring force of theboot 30 might have to be supplemented with a spring or other resilientmember.

This surface engagement between button 18 and grommet 14 is quiteeffective to provide a seal in the closed state for a smooth flowableproduct. It does not work well for products containing particles, forexample, peanut butter. It is believed that what happens is thatgranules of product are lodged between the engaging surfaces of thebutton 18 and the grommet 14. It is believed that these particles causeenough of a break in the sealing surface so that a pressure gradient isestablished across the sealing surface between the ambient pressure inthe valve stem passageway and the product pressure in the interior ofthe container. This pressure gradient results in the product adjacent tothe seal between grommet 14 and button 18 having a lower pressure thanthe pressure of the product within the dispensing container. The higherpressure is created by the pressurized gas in the pressure producingchamber. It is believed that this results in the peanut butter producthaving the oil and the denser product separate out when standing on theshelf. The result is that when the user actuates the valve, the productdispensed is not well mixed and initially the oil component is dispensedby itself. This is completely unsatisfactory to the user. The particlesthat cause this pressure gradient generally do not create sufficientpassageway to leak product in closed state.

Applicant believes that the above analysis is the explanation of whatoccurs in the use of prior art designs. But there may well be a somewhatdifferent explanation or, more likely, a supplementary explanation.

But, what has been found is that the use of a sealing cup 16 to effect ahigh pressure engagement with the grommet 14 provides an effective sealso that this product separation does not occur. Tests have been madewith peanut butter using the device of this invention and the resultshave been satisfactory in that the oil did not separate out.

As shown in FIGS. 1-3, the upper rim 20 of the sidewall 22 is chamferedto provide an annular sealing edge 38 that is a blunt knife like edge.This edge 38 transmits the full pressure from the pressurized productalong a narrow annular zone so as to provide a high pressure in psi inthe closed state at the lower surface 24 of the grommet 14. This assuresthat the resilient grommet 14 will be adequately deformed at the sealingzone created by the sealing edge 38. Because of the force of theengagement over the small surface area involved, product particles donot compromise the effective sealing. The engagement between sealing cup16 and button 18 is a press fit supplemented by a ridge 34 and recess 36engagement.

A presently preferred embodiment for use with the dispensing of peanutbutter is shown in FIG. 4. FIG. 4 shows only the stem 12 with its button18A and the sealing cup 16A. As shown therein, the stem 12 of the valveterminates in a button 18A. The sealing cup 16A has an annular sidewall22 which engages the button 18. This engagement may be press fit or bysnap fit or by both. As shown in FIG. 4, the preferred button includesan annular ridge 34A which snaps into a mating recess 36A in thesidewall 22 of the sealing cup 16.

The FIG. 4 embodiment shows an arrangement in which the thickness of thebutton 18A is greater than is usually the case. This thickness is chosenfor a tilt valve application so as to assure that the force of tiltingdoes not cause the sealing cup 16A to disengage. In the FIG. 4embodiment, the base 40A of the sealing cup 16A extends radially beyondthe sidewall 22A in order to provide a greater force from product underpressure to achieve and maintain an effective seal in the closed state.

In a vertically movable valve application, a press fit between a regularsize button and a sealing cup, together with a ridge 34 and groove 36engagement, as shown in FIGS. 1 through 3, would normally be adequate toassure retention of the sealing cup on the button.

The ridge 34 can be on either the inner surface of the annular sidewall22 or on the annular side surface of the button 18. In the FIG. 4embodiment, a ridge 34A and groove 36A arrangement is used to reinforcethe retention engagement effected by the thick button 18R.

In one preferred embodiment having the geometry shown in FIG. 2, thefollowing dimensions were found to be effective: A nylon sealing cup 16has a 35 mil (0.035 inch) thick annular sidewall 22, a 161 mil outerwall surface diameter, a 40 mil thick base and a 30 degree internalangle for the chamfer that creates the sealing edge 38. The edge 38 isabout three mils thick. A 369 mil ID for the sealing cup 16 engages a370 mil diameter button 18. The ridge 34 and groove 36 have a five milmaximum interference created by a 23 mil radius of curvature. In theclosed state, the sealing edge 38 depresses the grommet surface 24 byabout 10 to 20 mils. That would be a function of grommet durometer.

In another preferred embodiment having the geometry shown in FIG. 4, thefollowing dimensions were found to be effective: A 369 mil ID of thesealing cup 16 engages a 370 mil diameter button. The button 18A is made125 mils thick and has a ridge 34A that engages a groove 36A with amaximum of three mil interference created by a radius of curvature of 60mils.

FIG. 5 illustrates an application of the invention to a design which inthis particular case is for peanut butter. In the FIG. 5 design, anannular resilient tube 44 is used in conjunction with the nozzle 46having an annular hood 48. FIG. 5 is in the open state.

When the product is manufactured, the nozzle 46 is screwed all the waydown so that the hood 48 abuts against the mounting cup 15. In thiscondition, the resilient tube 44 is in compression and exerts a upwardforce on the nozzle 46 that pulls the stem 12 in an upward directionthereby assuring that the edge 38 of the sealing cup 16A forciblyengages the base surface 24 of the grommet 14.

In use, the user unscrews the nozzle 46 to a point where the rubber tube44 is held in position without exerting significant force. At thatpoint, the nozzle 46 can be tilted and product dispensed. When the userfinishes applying the peanut butter, the user screws the nozzle 46 toclose and seal the container. But as a practical matter, many users willnot screw the nozzle 44 all the way down to the point where the hood 48will engage the upper surface of the mounting cup 15. In some cases, therestoring force provided by the boot 30 of the grommet 14 will not exertenough force to make sure that the sealing edge 38 of the sealing cup16A will adequately engage the lower surface 24 of the grommet 14. Thecompression of the resilient tube 44, even if it is not fullycompressed, as when initially shipped, will provide sufficient restoringforce to assure engagement of the sealing edge 38 and grommet surface24.

As shown in FIG. 6, a cylindrical spring 50 in compression can beemployed in lieu of the resilient tube 44 so as to provide a closingforce. This closing force provided by tube 44 or spring 50 also servesto stabilize the valve stem.

Preferred embodiments of the invention have been disclosed. However, itwould be well within the understanding of one skilled in the art thatcertain variations can be made and stay within the scope of theteachings of this invention.

For example, the narrow sealing edge 38 could be created along the innerwall of the sealing cup 16 rather than the outer wall as shown. Indeed,this sealing edge 38 could be created at some intermediate positionbetween the inner wall and outer wall of the rim 20 of the sealing cup16.

Another example is that the sealing cup 16 could be created integrallywith the button 18. Such an approach will create molding problems andfor that reason is not preferred.

As shown in FIG. 4, in one preferred embodiment, the thickness of thebutton 18A is greater than is usually the case in order to assure thatin a tilt valve embodiment the sealing cup 16 will not rack on thebutton 18. Where a vertical valve operation is involved, then as shownin FIGS. 1 through 3, the button 18 may well be less thick than shown inFIG. 4. In such a case, an interference fit, without the annular ridge34 and recess 36 could be sufficient in some applications to maintainthe cup on the button. Experimentation in each application will berequired to determine the best fitting relationship between the sealingcup 16 and button 18 and whether or not the ridge 34 and recess 36engagement is required or useful.

The sealing cup 16 is preferably made of plastic. Nylon has been foundto be useful and a preferred material. The sidewall of the sealing cup16 is approximately 35 mils (0.035 inches) and the width of the sealingedge 38 is approximately three mils. However, it might be possible for ametal cup having a sidewall of 5 mils to be effectively used in certainsituations. In such an embodiment the rim 20 becomes the edge 38. Suchan embodiment is not presently preferred.

It is believed that it is desirable and preferable to avoid a sealingedge 38 so sharp as to cut the surface 24 of the resilient grommet 14.

As known in the art, the composition of the grommet 14 and of therestoring boot 30 and the composition of any restoring tube 44 or spring50 will depend on an appropriate combination thereof and trade off withthe range of product pressures from full to dispensed.

1. In a valve for use with a pressurized dispensing container, the valvehaving a stem and an annular resilient sealing grommet surrounding thestem, the improvement of a sealing element at the base of the stemcomprising: a cup shaped sealing element connected to the stem andhaving an annular sidewall extending up from said stem base, saidsidewall having an upper annular edge that sealingly engages the grommetwhen the valve is in its closed state.
 2. The improvement of claim 1wherein: said upper edge is narrower than the thickness of said annularsidewall.
 3. The improvement of claim 1 wherein: the grommet has a lowerflat surface and said upper edge of said sealing cup engages said lowersurface of the grommet when the valve is in a closed state.
 4. Theimprovement of claim 2 wherein: the grommet has a lower flat surface andsaid upper edge of said sealing cup engages said lower surface of thegrommet when the valve is in a closed state.
 5. The improvement of claim1 wherein: the stem has a button and said annular sidewall of saidsealing cup is press fit onto said button.
 6. The improvement of claim 1wherein: said stem has a button, said button has a sidewall and furthercomprising: an annular groove and ridge engagement between saidsidewalls of said button and said cup.
 7. The improvement of claim 4wherein: said button and said sealing element are integral.
 8. Theimprovement of claim 4 wherein: said sealing element has a base and saidbase extends radially outward past said sidewall of said sealingelement.
 9. The improvement of claim 6 wherein: said button has athickness adequate to prevent said sealing element from rocking loose.10. The improvement of claim 2 wherein: said sealing edge is at theouter surface of said sidewall of said sealing element.
 11. Theimprovement of claim 4 wherein: said sealing edge is at the outersurface of said sidewall of said sealing element.
 12. The improvement ofclaim 5 wherein: said button is spaced from said grommet when said valveis in said closed state.
 13. The improvement of claim 6 wherein: saidbutton is spaced from said grommet when said valve is in said closedstate.
 14. The improvement of claim 9 wherein: said button is spacedfrom said grommet when said valve is in said closed state.
 15. Theimprovement of claim 1 wherein the valve has a mounting cup, furthercomprising: a resilient tube in compression engaging the mounting cupand the stem to provide a restoring force to close the valve whendispensing pressure is removed.
 16. The improvement of claim 4 whereinthe valve has a mounting cup, further comprising: a resilient tube incompression engaging the mounting cup and the stem to provide arestoring force to close the valve when dispensing pressure is removed.17. The improvement of claim 9 wherein the valve has a mounting cup,further comprising: a resilient tube in compression engaging themounting cup and the stem to provide a restoring force to close thevalve when dispensing pressure is removed.
 18. The improvement of claim1 wherein the valve has a mounting cup, further comprising: a resilienttube in compression engaging the mounting cup and the stem to provide arestoring force to close the valve when dispensing pressure is removed.19. The improvement of claim 4 wherein the valve has a mounting cup,further comprising: a resilient tube in compression engaging themounting cup and the stem to provide a restoring force to close thevalve when dispensing pressure is removed.
 20. In a valve for use with apressurized dispensing container, the valve having a stem and an annularresilient sealing grommet surrounding the stem, said grommet having alower surface, the improvement of a sealing element at the base of thestem comprising: a cup shaped sealing element connected to the stem andhaving an annular sidewall extending up from said base, said sidewallhaving an annular upper edge that is narrower than the thickness of saidsidewall, the grommet having a lower flat surface and said upper edge ofsaid sealing cup engaging said lower surface of the grommet when thevalve is in a closed state, said stem having a button, said buttonhaving a sidewall, an annular groove and ridge engagement between saidsidewalls of said button and said cup, said button being spaced fromsaid grommet when said valve is in its closed state.